This disclosure relates to a medical device and more particularly to implantable neurological electrical stimulators and implantable electrical stimulation leads.
The medical device industry produces a wide variety of electronic and mechanical devices for treating patient medical conditions such as pacemakers, defibrillators, neurostimulators, and therapeutic substance delivery pumps. Medical devices can be configured to be surgically implanted or connected externally to the patient receiving treatment. Clinicians use medical devices alone or in combination with therapeutic substance therapies and surgery to treat patient medical conditions. For some medical conditions, medical devices provide the best and sometimes the only therapy to restore an individual to a more healthful condition and a fuller life. One type of medical device is an implantable neurological stimulation system that can be used to treat conditions such as pain, movement disorders, pelvic floor disorders, gastroparesis, and a wide variety of other medical conditions. The neurostimulation system typically includes a neurostimulator, a stimulation lead, and an extension such as shown in Medtronic, Inc. brochure “Implantable Neurostimulation System” (1998).
Previous extensions are typically formed using a solid conductor formed from a material that is a reasonably good compromise between the mechanical properties required to form electrical connections and the conductive properties required to efficiently conduct the stimulation signal from the neurostimulator to the stimulation lead. The compromise of material used in a solid conductor results in higher impedance than is desired. The extension's higher impedance than desired can result in increased power consumption and decreased battery life. An example of an extension that uses a solid conductor is shown in Medtronic, Inc. brochure “Model 7495 Extension Kit for Stimulation of the Brain, Spinal Cord, or Peripheral Nerves” (2000). An example of a low impedance lead used for cardiac pacing and defibrillation typically having only one or two conductors is shown in U.S. Pat. No. 5,330,521 “Low Resistance Implantable Electrical Leads” by Cohen (Jul. 19, 1994).
For the foregoing reasons, there is a need for a low impedance extension that decreases power consumption and has many other improvements.